(5 October 1907). The Spell Too Yiddish, The Billboard, p. 6 ("As the heroine's mother, Emily Rigl made a great hit with the audience, by the wonderfully realistic and comic touch she gave the role.")
fultonhistory.com
(2 July 1898). Obituary, New York Dramatic Mirror (Whitney obituary)
(27 June 1903). Obituary, New York Dramatic Mirror (reporting death of Betty's son Francis X. Whitney)
josephhaworth.com
Emil Rigl, josephhaworth.com, Retrieved 21 March 2013